Scroll compressors are known and typically include a closed container. A compression unit is disposed in the closed container, including a fixed scroll including a fixed base plate and a fixed spiral wrap, and an orbiting scroll including an orbiting base plate and an orbiting spiral wrap. The fixed spiral wrap and the orbiting spiral wrap fit together, forming a plurality of compression chambers.
Scroll compressors typically further include a drive shaft including a driving portion configured to drive the orbiting scroll in an orbital movement. An Oldham coupling is configured to prevent rotation of the orbiting scroll with respect to the fixed scroll.
The Oldham coupling typically includes an annular ring having a first side and a second side opposite to the first side A first and a second engaging projection are configured to be slidably engaged to a first and a second complementary engaging groove provided on the fixed scroll of the scroll compressor. The first and second engaging projections are diametrically opposed to each other and projecting from the first side of the annular ring.
The Oldham coupling typically further includes a third and a fourth engaging projection configured to be slidably engaged with a third and a fourth complementary engaging groove provided on the orbiting scroll of the scroll compressor. The third and fourth engaging projections are diametrically opposed to each other and project from the second side of the annular ring. The third and fourth engaging projections are angularly offset from the first and second engaging projections by an angle of about 90°.
Such a location of the first, second, third and fourth engaging projections decreases space for the fixed and orbiting spiral wraps on the scroll compressor. This limits the displacement of the compression unit and thereby limits the performances of the scroll compressor.
Further the configuration of the first, second, third and fourth engaging projections results in a significant tipping moment of the Oldham coupling, which may lead to a twisting of the Oldham coupling. This twisting may induce an improper sliding of the first, second, third and fourth engaging projections in the first, second, third and fourth engaging grooves, and may harm the efficiency of the compression unit.
Moreover, due to the fact that an Oldham coupling is usually made of a low weight material, and particularly of aluminium, the first, second, third and fourth engaging projections may possibly break under the mechanical stresses applied on said engaging projections, which may be detrimental to the reliability of the scroll compressor.